In 1990, employers reported a 21% increase in general health care expenditures and reported cost increases in mental health of up to 60% a year. One response seen in the private and public sector has been to "carve-out" their mental health benefit from their medical benefit, and contract with an outside vendor to manage treatment patterns and control costs. This mental health carve-out provides the intervention whose effects this study will analyze. This study addresses the use and costs of mental health and non-mental health care services in an employed population that has experienced a change in the organization and Cost of mental health coverage over time. The investigators employ the economic theory of demand to examine the determinants of mental health and medical care use before and after the introduction of the intervention, a mental health "carve-out". A three-stage demand model is estimated using pooled cross-sectional data adjusted for plan selection to determine the effects on individuals subjected to the intervention. The study is unique in that data are available on both users and non-users, for both mental and non- mental health care, from claims, HMO, and personnel files, and on those individuals who switched into or out of the plan three years prior to the carve-out (1988-1990) and three years after the carve-out (1991-1993).